1. Field of the Invention
The present invention relates generally to a system and method for providing location information, and in particular, to a system and method for providing location information of a terminal utilizing a Session Initiation Protocol (SIP) protocol.
2. Description of the Related Art
Various methods for location information requests and responses are available between a requestor (or client) that is requesting a location of a target terminal and a location server because each network may have a different location information request/response and location calculation process. Such request/response methods may also change according to the type of the location server. Therefore, a client generally uses different request/response methods according to the type of the location server, which often burdens a client terminal.
A Mobile Location Protocol (MLP) used in an Open Mobile Alliance Location (OMA LOC) working group is one example of a system for providing location information. The MLP, i.e., a protocol with a Transmission Control Protocol/Internet Protocol (TCP/IP) network used as a data delivery network, is used to request and deliver location service. More specifically, MLP is a location information request/response protocol used between a location server and a client terminal, by which Internet communication is usually performed. Accordingly, a client terminal connected to an Internet Protocol (IP) network can send a request for the location service to the location server and receive a response thereto using MLP. However, the client terminal can only send a request for the location service and receive a response thereto for a location server that uses the same request/response method as the terminal.
Because the type of the location server changes according to the type of the network, as described above, if a terminal is required to use a request/response method corresponding to each type of location server, this would be a heavy operation burden on the terminal. For example, a terminal and a location server in a Wideband Code Division Multiple Access (WCDMA) network should use a request/response method existing between them, and a separate location service request/response method exists even in a CDMA network. Likewise, MLP is also one of the location service request/response methods between a terminal connected to the IP network and a location server. If the terminal and the location server both have one unified request/response method, the terminal may receive location information using the various location servers.
When the location service is extended to other services, it is possible to provide enhanced services to users. For example, when location information of the terminal is provided during a voice call, it is possible to provide enhanced real-time voice service and multimedia service. A Session Initiation Protocol (SIP) protocol is used to provide the voice service, and the typical services using the SIP protocol include only the real-time voice service and the multimedia service. However, no detailed method has been proposed for the relevant standard technology for extending the SIP protocol to other services.
Accordingly, there is a demand for one common location information request/delivery method that would enable various types of clients and location servers to freely deliver location information requests/responses.